1. Field of the Invention
This invention relates in general to knee straps or braces useful for treating disorders of the knee, and more particularly to a compression band for treating soft tissue inflammation and patella-related disorders of the knee.
2. Prior Art
Chondromalacia of the patella is a common disorder and the result of normal motion of the patella with respect to the underlying femoral condyles. There have been a number of braces and straps devised to stabilize the patella and prevent such unwanted motion and to relieve the symptoms of chondromalacia patella.
Palumbo, in U.S. Pat. No. 4,370,978, issued Feb. 1st, 1983, and U.S. Pat. No. 4,296,744, issued Oct. 27, 1981, describes a brace suitable for treating certain patella-related disorders of the knee. The brace includes two para-patellar pads which function to stabilize the patella, an infra-patellar ligament pad which applies direct pressure to the patellar ligament, and a supra-patellar and an infra-patellar elastic strap which applies compressive force to the quadriceps mass and to the patellar ligament to diminish shock and compression and tensile forces to the extensor mechanism. The brace of Palumbo is substantially an elastic member with a circular region removed to overlie the patella. The construction of the brace is such that it restricts the motion of the leg and prevents the wearer from participating effectively in sports and the like. It is designed to stabilize the patella by splinting it. Moreover, the construction is such that, when the knee is bent, the compression of the popiteal region comprises a tourniquet, which further restricts the supply of blood to the lower extremity.
Gauvry, in U.S. Pat. No. 4,334,528, issued Jun. 15, 1982, describes yet another knee strap for treating chondromalacia patella and similar disorders. The Gauvry strap is substantially a section of surgical tubing which has been covered with a stockinet and encircles the leg so that the tubing overlies the patella thereby stabilizing it. The portion of the strap that directly overlies the patella is circular in cross-section and is narrower than the rest of the band. The band that fastens behind the knee is flat and wider than the front portion comprises a tourniquet when the knee is flexed. The pressure applied to the patellar tendon by the tubing is to prevent lateral motion of the patella during use. Beige, et al., U.S. Pat. No. 4,182,318 discloses a band useful for the treatment of epicondylitis. The band, dimensioned to encircle the elbow, comprises a pair of compression plates of unequal size which are in opposition to one another. The larger jaw engages the unaffected side of the inflicted elbow and, with its larger pressing surface, helps to prevent distortion of the underlying tissue. The smaller (opposing) jaw is dimensioned to apply more concentrated pressure on a smaller specific area. While the foregoing clamp is useful for treating epicondylitis, limitations presented by the asymmetry of the device limits its utility with respect to treating conditions of the knee. Nirschl, in U.S. Pat. No. 3,926,186, discloses a muscular support device for bracing muscles and tendons associated therewith. The device comprises a foam-backed cloth (canvas) wrap adapted for encircling the knee. The wrap applies circumferential pressure to the encircled underlying tissue. A portion of the wrap is contoured to avoid compressing the patella. The wrap is circumferential and supple, readily conforming to the contour of the underlying anatomy. The device necessarily applies circumferential compression to all of the underlying tissue; less pressure being exerted on the underlying skin where the skin-contacting surface of the wrap is larger and greater pressure where the skin-contacting surface is less. Thus, in operation, the wrap exerts a tourniquet effect, impairing the flow of blood to and from tissue distal to the knee.
In summary, prior art knee straps to treat problems associated with flexion and extension of the knee are directed toward stabilizing or splinting the patella to prevent the lateral displacement of the patella during activity. The present invention departs from the prior art in that it focuses on the motion of soft tissue over the femoral condyle during motion of the leg. The present invention teaches the use of a knee band for the treatment of flexion/extension-related disorders of the knee. The band has a compressive portion and a strap portion which holds the compressive portion in position. The band of the present invention is comfortable to wear and applies pressure only to those portions of the knee which are effective for preventing soft tissue microtrauma associated with the rapid acceleration/deceleration of the soft tissue folds of the knee during flexion and extension. The compressive portion of the band does not apply pressure to the patella and the strap portion is designed to minimize the tourniquet effect.